#include<stdio.h>
#include<stdlib.h>
#include<math.h>
int main()
{
	int i,j,k;
	int n;
	float *v;
	float p1,p2;
	float num,den,tmp;
	float w1,w2;
	scanf("%d",&n);
	v=(float *)malloc(sizeof(float)*n);
	for(i=0;i<n;i++) scanf("%f",&v[i]);
	num=0;
	den=0;
	p1=0;
	for(i=0;i<n;i++) p1+=v[i];
	p1/=n;
	w1=1000000000;
	w2=w1;
	printf("centroid is :%f\n",p1);
	while(w1<=w2)
	{
		w2=w1;
		w1=0;
		for(i=0;i<n;i++)
		{
			tmp=(v[i]-p1)*(v[i]-p1);
			tmp=sqrt(tmp);
			w1+=tmp;
			num+=v[i]/tmp;
			den+=1/tmp;
		}
		p1=num/den;
		printf("%f\n",p1);
	}
	printf("%f\n",p1);
	free(v);
	return 0;
}

